Spinal deformity derotation instrument

Abstract

A surgical instrument for correcting spinal deformities includes a tubular body adapted to receive a second instrument through the tubular body. The tubular body forms a transverse passage adapted to receive a longitudinal fixation element through the tubular body. The tubular body further includes first and second arms for connecting the surgical instrument to a vertebral anchor. The first and second arms include one or more anti-splaying features adapted to mate with anti-splaying features on the second instrument to prevent the first and second arms from splaying as the second instrument is inserted into the tubular body.

What is claimed: 
     
       1. A surgical instrument for correcting spinal deformities, the surgical instrument comprising a tubular body having a proximal end, a distal end opposite the proximal end, and a midsection extending between the proximal end and the distal end, the tubular body defining a longitudinal axis and a longitudinal passage extending along the longitudinal axis from the proximal end to the distal end, the longitudinal passage adapted to receive a second instrument through the tubular body,
 the tubular body further defining a first longitudinal slot and a second longitudinal slot opposite the first longitudinal slot, the first longitudinal slot and the second longitudinal slot terminating at the distal end of the tubular body and forming a transverse passage through the tubular body, the transverse passage adapted to receive a longitudinal fixation element through the tubular body, 
 the tubular body further comprising a first extension and a second extension opposite the first extension, the first extension separated from the second extension by the first longitudinal slot and the second longitudinal slot, the first extension comprising a first pivot arm for detachably connecting the surgical instrument to a first connector on a vertebral anchor and a second pivot arm for detachably connecting the surgical instrument to a second connector on the vertebral anchor, the first pivot arm having a first activation end and a first attachment end opposite the first activation end, and the second pivot arm having a second activation end and a second attachment end opposite the second activation end, 
 the first pivot arm defining a first anti-splaying slot extending from the first activation end to the first attachment end, and the second pivot arm defining a second anti-splaying slot extending from the second activation end to the second attachment end, at least one of the first anti-splaying slot and the second anti-splaying slot being open in a radial direction toward the longitudinal axis and open to the longitudinal passage to receive an anti-splaying element on the second instrument. 
 
     
     
       2. The surgical instrument of  claim 1 , wherein the tubular body defines a first elongated aperture, at least a portion of which extends into the first extension, and a second elongated aperture, at least a portion of which extends into the second extension. 
     
     
       3. The surgical instrument of  claim 2 , wherein the first pivot arm is pivotally mounted in the first elongated aperture and the second pivot arm is pivotally mounted in the second elongated aperture. 
     
     
       4. The surgical instrument of  claim 2 , wherein the first pivot arm is mounted in the first elongated aperture by a first pivot connection, and the second pivot arm is mounted in the second elongated aperture by a second pivot connection. 
     
     
       5. The surgical instrument of  claim 4 , wherein the first activation end of the first pivot arm is connected to the first attachment end by a first dog leg section, and the second activation end of the second pivot arm is connected to the second attachment end by a second dog leg portion. 
     
     
       6. The surgical instrument of  claim 5 , wherein the first anti-splaying slot defines a first aperture in the first dog leg section facing the proximal end of the tubular body, the first aperture configured to axially receive a first anti-splaying element on the second instrument, and wherein the second anti-splaying slot defines a second aperture in the second dog leg section facing the proximal end of the tubular body, the second aperture configured to axially receive a second anti-splaying element on the second instrument. 
     
     
       7. The surgical instrument of  claim 5 , wherein the first pivot arm is connected to the first pivot connection at the first dog leg section, and the second pivot arm is connected to the second pivot connection at the second dog leg section. 
     
     
       8. The surgical instrument of  claim 1 , wherein the first pivot arm and the second pivot arm are pivotally displaceable relative to the tubular body between an attachment position, in which the first attachment end and the second attachment end are attachable to the vertebral anchor, and a release position, in which the first attachment end and the second attachment end are removable from the vertebral anchor. 
     
     
       9. The surgical instrument of  claim 8 , wherein the first activation end of the first pivot arm is closer to the longitudinal axis in the release position than in the attachment position, and the second activation end of the second pivot arm is closer to the longitudinal axis in the release position than in the attachment position. 
     
     
       10. The surgical instrument of  claim 8 , further comprising a first biasing element that biases the first pivot arm toward the attachment position and a second biasing element that biases the second pivot arm toward the attachment position. 
     
     
       11. The surgical instrument of  claim 10 , wherein the first biasing element comprises a first spring that exerts a first radially outward biasing force on the first activation end of the first pivot arm, and the second biasing element comprises a second spring that exerts a second radially outward biasing force on the second activation end of the second pivot arm. 
     
     
       12. The surgical instrument of  claim 11 , wherein the first pivot arm and the second pivot arm are pivotally displaceable against the first radially outward biasing force and the second radially outward biasing force, and toward the release position, in response to radially inward forces applied to the first activation end and the second activation end of the first pivot arm and the second pivot arm, respectively. 
     
     
       13. The surgical instrument of  claim 11 , wherein pivotal displacement of the first pivot arm and the second pivot arm to the release position compresses the first spring and the second spring under stored energy. 
     
     
       14. The surgical instrument of  claim 11 , wherein the first activation end of the first pivot arm comprises a first recess that receives the first spring, and the second activation end of the second pivot arm defines a second recess that receives the second spring. 
     
     
       15. The surgical instrument of  claim 8 , wherein the first activation end of the first pivot arm projects radially outwardly from the first aperture when the first pivot arm is in the attachment position, and the second activation end of the second pivot arm projects radially outwardly from the second aperture when the second pivot arm is in the attachment position. 
     
     
       16. The surgical instrument of  claim 8 , wherein the first aperture comprises a first stop for limiting pivotal displacement of the first pivot arm beyond the attachment position and a second stop for limiting pivotal displacement of the first pivot arm beyond the release position. 
     
     
       17. The surgical instrument of  claim 8 , wherein the first attachment end of the first pivot arm extends into the longitudinal passage when the first pivot arm is displaced to the attachment position, and the second attachment end of the second pivot arm extends into the longitudinal passage when the second pivot arm is displaced to the attachment position. 
     
     
       18. The surgical instrument of  claim 8 , wherein the first attachment end of the first pivot arm is outside of the longitudinal passage when the first pivot arm is displaced to the release position, and the second attachment end of the second pivot arm is outside of the longitudinal passage when the second pivot arm is displaced to the release position. 
     
     
       19. The surgical instrument of  claim 1 , wherein the proximal end of the tubular body comprises a connection element for axially guiding the second instrument inside the longitudinal passage. 
     
     
       20. A surgical instrument for correcting spinal deformities, the surgical instrument comprising a tubular body having a proximal end, a distal end opposite the proximal end, and a midsection extending between the proximal end and the distal end, the tubular body defining a longitudinal axis and a longitudinal passage extending along the longitudinal axis from the proximal end to the distal end, the longitudinal passage adapted to receive a second instrument through the tubular body,
 the tubular body further defining a first longitudinal slot and a second longitudinal slot opposite the first longitudinal slot, the first longitudinal slot and the second longitudinal slot terminating at the distal end of the tubular body and forming a transverse passage through the tubular body, the transverse passage adapted to receive a longitudinal fixation element through the tubular body, 
 the tubular body further comprising a first extension and a second extension opposite the first extension, the first extension separated from the second extension by the first longitudinal slot and the second longitudinal slot, the first extension comprising a first pivot arm for detachably connecting the surgical instrument to a first connector on a vertebral anchor and a second pivot arm for detachably connecting the surgical instrument to a second connector on the vertebral anchor, the first pivot arm having a first activation end and a first attachment end opposite the first activation end, and the second pivot arm having a second activation end and a second attachment end opposite the second activation end, 
 the first pivot arm defining a first anti-splaying slot extending from the first activation end to the first attachment end, the first anti-splaying slot being open to the longitudinal passage and adapted to receive a first anti-splaying element on the second instrument, and the second pivot arm defining a second anti-splaying slot extending from the second activation end to the second attachment end, the second anti-splaying slot being open to the longitudinal passage and adapted to receive a second anti-splaying element on the second instrument, 
 wherein the first pivot arm and the second pivot arm are pivotally displaceable relative to the tubular body between an attachment position, in which the first attachment end and the second attachment end are attachable to the vertebral anchor, and a release position, in which the first attachment end and the second attachment end are removable from the vertebral anchor, and 
 wherein the surgical instrument further comprises a first biasing element that biases the first pivot arm toward the attachment position and a second biasing element that biases the second pivot arm toward the attachment position. 
 
     
     
       21. The surgical instrument of  claim 20 , wherein the first biasing element comprises a first spring that exerts a first radially outward biasing force on the first activation end of the first pivot arm, and the second biasing element comprises a second spring that exerts a second radially outward biasing force on the second activation end of the second pivot arm. 
     
     
       22. The surgical instrument of  claim 21 , wherein the first pivot arm and the second pivot arm are pivotally displaceable against the first radially outward biasing force and the second radially outward biasing force, and toward the release position, in response to radially inward forces applied to the first activation end and the second activation end of the first pivot arm and the second pivot arm, respectively. 
     
     
       23. The surgical instrument of  claim 21 , wherein pivotal displacement of the first pivot arm and the second pivot arm to the release position compresses the first spring and the second spring under stored energy. 
     
     
       24. The surgical instrument of  claim 21 , wherein the first activation end of the first pivot arm comprises a first recess that receives the first spring, and the second activation end of the second pivot arm defines a second recess that receives the second spring. 
     
     
       25. A surgical instrument for correcting spinal deformities, the surgical instrument comprising a tubular body having a proximal end, a distal end opposite the proximal end, and a midsection extending between the proximal end and the distal end, the tubular body defining a longitudinal axis and a longitudinal passage extending along the longitudinal axis from the proximal end to the distal end, the longitudinal passage adapted to receive a second instrument through the tubular body,
 the tubular body further defining a first longitudinal slot and a second longitudinal slot opposite the first longitudinal slot, the first longitudinal slot and the second longitudinal slot terminating at the distal end of the tubular body and forming a transverse passage through the tubular body, the transverse passage adapted to receive a longitudinal fixation element through the tubular body, 
 the tubular body further comprising a first extension and a second extension opposite the first extension, the first extension separated from the second extension by the first longitudinal slot and the second longitudinal slot, the first extension comprising a first pivot arm for detachably connecting the surgical instrument to a first connector on a vertebral anchor and a second pivot arm for detachably connecting the surgical instrument to a second connector on the vertebral anchor, the first pivot arm having a first activation end and a first attachment end opposite the first activation end, and the second pivot arm having a second activation end and a second attachment end opposite the second activation end, 
 the first pivot arm defining a first anti-splaying slot extending from the first activation end to the first attachment end, the first anti-splaying slot being open to the longitudinal passage and adapted to receive a first anti-splaying element on the second instrument, and the second pivot arm defining a second anti-splaying slot extending from the second activation end to the second attachment end, the second anti-splaying slot being open to the longitudinal passage and adapted to receive a second anti-splaying element on the second instrument, 
 wherein the first pivot arm and the second pivot arm are pivotally displaceable relative to the tubular body between an attachment position, in which the first attachment end and the second attachment end are attachable to the vertebral anchor, and a release position, in which the first attachment end and the second attachment end are removable from the vertebral anchor, and 
 wherein the first attachment end of the first pivot arm extends into the longitudinal passage when the first pivot arm is displaced to the attachment position, and the second attachment end of the second pivot arm extends into the longitudinal passage when the second pivot arm is displaced to the attachment position.